New gene family of antimicrobial proteins discovered in German cockroaches

Researchers from The Institute for Integrative Systems Biology have discovered a new gene family of antimicrobial peptides (small proteins) – the Blattellicins – in a German cockroach (Blattella germanica).

The study, published in the journal Scientific Reports, may help to understand how these insects can live in unsanitary environments and defend themselves against the fungal and bacterial pathogens they encounter via the beneficial symbiotic organisms that they harbor.

"The German cockroach is one of the most successful cockroach species as an urban pest associated with human populations. The study shows that one of the factors that have contributed to its success is the increase in the number of genes that encode antimicrobial proteins. Also, the presence of Blattellicins, the new family of antimicrobial proteins, could provide greater effectiveness against some pathogens," highlights Francisco J. Silva.

The function of these new proteins is unknown, but they could be antimicrobial proteins of greater efficacy or favor the formation of pores in the endosymbiont membrane, which facilitates the transfer of metabolites to the insect's cells.

Thus, Blattellicin genes, which have recently evolved from Atacin genes – another type of antimicrobial peptide – could contribute to defend against fungal and bacterial pathogens.